DESERTS: THREE MAJOR TYPES OF DESERTS
In a desert, annual precipitation is low and often scattered unevenly throughout the year. During the day, the baking sun warms the ground and evaporates water from plant leaves and the soil. But at night, most of the heat stored in the ground radiates quickly into the atmosphere. Desert soils have little vegetation and moisture to help store the heat and the skies above deserts are usually clear. This explains why in a desert you may roast during the day but shiver at night. The lack of vegetation, especially in tropical and polar deserts, makes them vulnerable to sandstorms driven by winds that can spread sand from one area to another. Desert surfaces are also vulnerable to disruption from vehicles such as SUVs. A combination of low rainfall and varying average temperatures creates tropical, temperate, and cold deserts. 1. TROPICAL DESERTS: Tropical deserts such as the Sahara and the Namib of Africa are hot and dry most of the year. They have few plants and a hard, windblown surfac